With the popularity of on-board front imaging equipment, many vehicles are equipped with on-board front imaging equipment. The equipment is usually installed inside a car and outward, located in the front of the car, with a driving recorder function which can be used to monitor the road condition around the car during driving, and record all the images along the forward direction of the car. The main purpose of the equipment is obtaining evidences effectively when a traffic accident occurs, at the same time, the equipment can be used to record the beautiful scenery and the driving trajectory along the way. In addition, the equipment can also provide reliable data for intelligent algorithms such as on-road parking capture, algorithm of license recognition and so on.
However, the present on-board front imaging equipment is susceptible to illumination, which can't avoid overexposing or underexposing of the region of interest on the premise of ensuring the clarity of the overall image, and narrowing the scope of application, and it's not conducive to the promotion of on-board front imaging equipment. This is because the present equipment is usually use single-point evaluation or overall evaluation as the method used to evaluate the region of interest, to guarantee clarity of the overall image will induce the situation of overexposing or underexposing of the region of interest, it's difficult for the present equipment to adapt to the special requirements for intelligent algorithms under any illumination or scene outside the car, for example, it's easy overexposing local part of the image in the midday sun and underexposing the areas beside the car in low light, therefore the scope of application is narrow, which is not conducive to the promotion of on-board front imaging equipment.